intense itching and mucus... Anal Fissure?

About 1 and a half years ago, I noticed my anus was itching. I immediately assumed it was worms but was too embarassed to say. My brother got worms a few weeks later so I took the tablets as a "precaution" not letting on that I thought I had them too.
The itching didn't stop and, having scraped out my anus with some tissue, I noticed a thick, yellow/white paste which smelt very bad and very strange. This relieved all itching for a few days so I wondered whether it was the source of the problem. Unfortunately, more accumulated and every few days, I would scrape this stuff out.
It began to become routine but I knew I would have to find a cure at some point. I am 15 and I didn't want anyone to find out due to the embarrassment. The itchiness worsened and I now have to scrape out the "paste" 2-3 times a day. Sometimes, the itch wakes me up at night and my sleeping is restless. I usually feel very tired, even after 9 hours of sleep.
I can't remember at what point but I also noticed I had a cut in my anus and scraping the paste out would cause it to bleed. Having read up on this, I found out that it was an anal fissure and I may have had it the whole time. The symptoms included bright red blood on tissue paper and a burning sensation during/after bowel movements, both of which I had experienced. Further symptoms can include intense itching and mucus in the anus. These almost completely fit my condition however, I wouldn't describe it as "mucus" but, as I said, more of a thick paste.
Is it possible that I have worms and the fissure was caused by scraping out the paste or did I have the fissure all along and thats all that needs treating? What makes me think that it might not be worms is that the pills didn't work and normally, I would have experienced worse symptoms from them by now like stomach pains - its been over a year.
Equally, I am unsure that it's a fissure because of the paste. If its a fissure, why would more and more be being produced - that makes me think it could be due to an increasing worm population?? but then, how can it come from them?
Any help and advice would be very much appreciated! Thankyou